The systems and techniques presented herein relate to radio frequency (RF) communication over a short distance, and more particularly, to the transmission of short range RF communication signals in the presence of constant and intermittent interferers having strong power relative to the communication signal power.
With the continuing increase in wireless data transmission between devices, more systems have come to depend on the availability of such wireless transmission of data. Many of these systems rely upon radio-frequency (RF) communications systems to provide such wireless data transport. In order to maintain the effectiveness of such wireless links, it is important that wireless connections, especially those that provide critical data or that operate in environments with high levels of electromagnetic interference (EMI), remain able to communicate effectively with one another.
The EMI in a communications environment can cause problems with the communication system because of the persistence and duration of the EMI. In addition, the received interference signal power and interference signal spectral content also can cause problems with the communication system. Further, the uncertainty of the EMI interference is also a factor that can cause problems with a communication system. Specifically, strong communication signals may exhibit extended persistence but have a spectral composition of limited width when compared to an interfering signal composed of periodic pulses of relatively low duty cycle. However, the limited duration of the interference pulses imparts a wide spectral content to the interfering signal, and the shorter the duration of the pulse then the wider the interfering spectrum.
Yet another consideration to be considered when adopting a short range RF communications system is the impact the communication system, itself, has on other users. In a first consideration, the Federal Communications Commission (FCC) has promulgated regulations respecting the transmission of radio signals and these regulations must be observed. In a second consideration, the short range RF communications can constitute EMI to control and other electronics within the host aircraft.
Therefore a desire exists to provide operationally reliable RF communications link between devices that operate in a high EMI environment, while remaining compatible with regulations and with ancillary electronics.